Dynamic mechanical behavior of Laser Powder Bed fused near-beta Ti5553 alloy at elevated temperatures

Abstract

The lack of study on the effect of elevated temperature on the dynamic response of LPBF-made Ti-5Al-5Mo-5V-3Cr (Ti5553) restricts its use in aerospace structures. Dynamic compression tests were performed at 298, 473, and 673 K using a Split Hopkinson Pressure Bar. At 298 K, the alloy exhibits high strength, reaching an ultimate compressive strength of ∼ 1200 MPa at 600 s −1, limited ductility (0.069), Increasing the temperature to 473 K reduces the strength to ∼ 1030 MPa at 1000 s −1 while increasing ductility (0.10). At 673 K, the strength further decreases to ∼ 840 MPa at 1900 s −1, whereas ductility increases significantly (0.20), resulting in a marked rise in toughness. Microstructural analysis shows that room-temperature deformation involves slip, grain fragmentation, and gradual texture transition. Higher temperature activates dynamic recovery and strengthens shear localization. At 673 K, grain flattening and partial discontinuous dynamic recrystallization appear, also, formation of well-defined adiabatic shear bands.